Ice maker

ABSTRACT

There is disclosed an icemaker for installation in a household refrigerator. An increase in ice production capability is provided by providing a cold air flow path around the exterior of the ice mold. Means can be provided to prevent cold air passage across the mold during ice harvesting.

United States Patent 1191 1111 3,828,568 Frazier Aug. 13, 1974 ICE MAKER2,886,747 5/1959 DiebOld 317/234 3,025,679 3/1962 Keighley 62/186 X [75]Invent Loulsvlne, 3,146,606 9/1964 Grimes et al. 62/351 x Assignee:General Electric Company, Archer Louisville, Ky.

Primary Examiner-William E. Wayner [22] F 1972 Attorney, Agent, orFirm-Francis H. Boos [21] Appl. No.: 318,715

[57] ABSTRACT [52] U.S. Cl. 62/186, 62/351 [51] Int. Cl. F25c l/06 Thered'sclosed an cemaker for mstallanon m a 5 Field of Search 62/35l 356,353 340 household refrigerator. An increase in ice production (52/426,capability is provided by providing a cold air flow path around theexterior of the ice mold. Means can be [56] References Cited provided toprevent cold air passage across the mold UNITED STATES PATENTS dumgharvestmg' 2,782,608 2/1957 French et al 62/356 X 6 Claims, 6 DrawingFigures PATENTEB AUG 1 3 m4 sum 1hr 3 PAIENIE we 1 31974 sum 2 BF 3EiiliZ PAIENIEB ms x 31914 '3'.aaa.see

ICE MAKER The provision of icemakers in household refrigerators is quitecommon. Typical icemakers proposed by the prior art are found in U.S.Pats. No. 3,163,017 and 3,163,018. In the commercial design of thesedevices, the ice mold comprises a cast aluminum block having heatexchange fins thereon. Accordingly, the ice mold of the prior art isrelatively massive thus requiring substantial material expense. In thesedisclosures, an ice mold having a plurality of upwardly facing ice cubecavities is disposed beside a motor and linkage mechanism for ejectingice pieces from the cavities. Although these icemakers have provedacceptable, certain improvements in mounting flexibility, spaceconservation, ice making efficiency and ice harvesting efficiency arecontemplated by this invention.

It has been learned that greater mounting flexibility and spaceconservation can be achieved by positioning the motor and linkagemechanism for the ice ejector below the ice mold rather than beside thesame.

Ice making efficiency of the device of this invention is improved overthat of the prior art by providing a cold air passage around the mold.Turbulent cold air movement in the passage results in improved heattransfer across the mold thereby resulting in greater ice production.

Ice harvesting efficiency is improved in the device of this invention byclosingthe cold air passage at the inception of ice harvesting therebyminimizing heat transfer across the mold during the ice harvesting cy-IN THE DRAWINGS FIG. 1 is a cross sectional view of a cold storageappliance illustrating the icemaker of this invention in one operativeconfiguration thereof;

FIG. 2 is an enlarged front elevation view of the icemaker of thisinvention, certain parts being broken away for clarity of illustrationand illustrating the icemaker during the icemaking'cycle;

FIG. 3 is a broken view similar to FIG. 2, certain parts being omittedfor clarity, illustrating the icemaker at the inception of the iceharvesting cycle;

FIG. 4 is a view similar to FIG. 3 illustrating the ejector mechanism inthe ice piece ejecting position;

FIG. 5 is a horizontal cross sectional view of the icemaker of FIGS. 1-4taken substantially along line 5-5 of FIG. 2 as viewed in the directionindicated by the arrows; and

FIG. 6 is a schematic view of a typical electrical control circuit whichmay be utilized with the icemaker of this invention.

Referring to FIG. 1, the icemaker 10 of this invention is illustrated aspositioned in the freezing compartment cle. Consequently, a lowercapacity heater may be utilized to warm the mold in order to free theice pieces for ejection. Ice harvesting efficiency is also improved bythe design of the ejector linkage mechanism.

It is an object of this invention to provide an ice maker having greatermounting flexibility, increased ice production capability, increased iceharvesting efficiency and achieving greater space utilization.

In summary, one aspect of this invention comprises an icemaker includinga mold having an inner surface providing ice piece forming cavities andan outer surface; a housing around the mold, the housing and the outermold surface defining therebetween a serpentine .path of cold airmovement for abstracting heat from the mold; and means for harvestingice from the mold.

Another aspect of this invention comprises a cold storage appliancehaving a freezing compartment defined by a plurality of walls and meansfor circulating cold air in the compartment; and an ice maker, in thecompartment, comprising a mold having an inner surface providing icepiece forming cavities and an outer surface; a housing, independent ofthe compartment walls, around the mold and defining with the outer moldsurface a path of cold air movement; and means for harvesting ice piecesfrom the cavities including a heater for warming the inner mold surfaceand means for removing ice pieces from the cavities.

A further aspect of this invention comprises an icemaker including amold providing ice piece forming cavities, means providing a cold airpassage in heat exchanging relation with the mold, means operativeduring ice harvesting for removing ice from the mold including a heaterfor warming the mold, and means operative during harvesting forrestricting the passage.

Other aspects, features and advantages of this invention will becomemore apparent hereinafter.

12 of a cold storage appliance. The freezing compartment 12 is definedby a bottom wall 14, side walls 16, a back wall 18 and an open frontwhich is closed by a conventional door (not shown). Opening through theback wall 13 is a duct 20 having therein a fan 22 for circulating coldair through the compartment 12. The fan 22 is typically controlled by asuitable thermostat (not shown) for starting and stopping cold aircirculation in the compartment 12 in response to temperature therein. Aswill become more fully apparent hereinafter, the fan 22 comprises meansfor circulating cold air in the compartment 12 through the icemaker 10.

In order to assure that cold air passes through the icemaker 10 in theappropriate direction and in order to assure a substantial quantity ofcold air moving through the icemaker 10, there is preferably provided afitting 24 secured to the back wall 18 adjacent the duct 20. The fitting24 acts to deliver a predetermined ratio of air from the fan 22 to aflexible conduit 26 connected to the icemaker 10.

For purposes of illustration, the icemaker I0 is illustrated adjacentthe left side wall of the compartment 12 as viewed from the open frontwith an ice storage container 28 adjacent thereto. A prototype of theicemaker 10 is approximately 2- /2 inches wide X 7-% inches high X 9inches deep. Accordingly, in many installations, the icemaker 10 may beplaced on the freezer bottom wall with a shelf thereabove. As will bemore fully apparent hereinafter, the icemaker 10 is unit handled and maybe positioned adjacent either side or the back of the compartment 12.

Referring to FIGS. 2-6, the icemaker 10 comprises as major components amold 30, a housing or baffle 32 defining with the mold 30 an undulatingor serpentine cold air passage 34, ice harvesting means 36 including aheater 38, an ejector 40, driving means 42 and a linkage 44interconnecting the driving means 42 and the ejector 40, a valve 46 forrestricting the cold air passage 34 during harvesting, and a circuit 48for controlling operation of the various components during the icemakingand ice harvesting cycles.

The mold 30 includes an inner surface 50 providing a pluraity ofupwardly facing ice piece forming cavities 52. For all practicalpurposes, the inner mold surface 50 is substantially the same asillustrated in US. Pat. No. 3,163,017 and 3,331,215. The mold 30 alsoincludes an outer moldsurface 54 of substantially the same configurationas the inner surface 50. The mold 30 is accordingly a thin wall mold ascontrasted with the disclosures of the prior art referred to previously.The outer mold surface 54 presents an undulating surface rather than aplanar surface as shown in the prior art. The mold 30 also includes abottom wall 56 spaced below the bottom of the cavities 52 (FIG. 4) inorder to accommodate the ejector 40 in the icemaking position thereof asshown in FIG. 2. The mold 30 may also comprise a top wall 58 forsecurement to the frame 60 of the icemaker 10.

Referring to FIGS. 1 and 2, there is provided a filling trough 62connected to a suitable water line 64 passing through the side wall 16of the freezing compartment 12. As will be apparent from FIG. 2, thefilling trough 62 may be connected on either end of the icemaker 10which enhances mounting. flexibility thereof. Water flowing through theconduit 64 and the filling trough 62 into the mold 30 is controlled by avalve 66 (FIG. 6) having a solenoid 68 which, when energized, opens thevalve 66 to permit water to enter the filling trough 62 and mold 30.Since the opening into the filling trough 62 may be through the sidewall, as illustrated, or through the end wall, mounting flexibility isfurther enhanced.

The housing 32 is captivated by the frame 60 between openings 70, 72therein and is in surrounding relation to the mold 30. The direction ofair movement along the passage 34 depends, of course, upon the naturalcirculation pattern. within the freezing compartment 12 or the inducedcirculation pattern afforded by the fitting 24 and the conduit 26. Forpurposes of illustration, air flow is illustrated from right to left inFIG. since it is desirable that the thermostat 74 be in heattransferring relation with the downstream ice forming cavity 52.

The housing 32 comprises side walls 76, 78 which undulate in anarrangement complementary to the undulations in the mold 30 therebyproviding the undulating or serpentine air flow passage 34. Theconfiguration of the air flow passage 34 and the distances between themold 30 and the side walls 76, 78 are designed to achieve turbulent airflow in the passage 34 at volumetric air flows between 1 and CFM.Turbulent air flow in the passage 34 is highly desirable to avoid deadair spaces in the areas 80 between the ice piece forming sections. Thehousing 32 also comprises a bottom wall 82 underlying the mold 30 asseen most clearly in FIGS. 3 and 4. I

Testing of various prototypes of this invention has revealed interestingdata. In an early prototype of the invention with a housing havingplanar side walls rather than undulating side walls with the cold aircirculating fan on continuously, the elapsed time from filling of theice piece cavities with water to freezing of the ice pieces was greaterthan 60 minutes. By incorporating means on the baffle side walls tocreate a serpentine cold air flow path and thereby provide turbulent airflow reduced the fill-to-freeze time to 40 minutes. It will beappreciated that the ice mold 30 and baffle 32 of this invention aresubstantially less expensive than the cast aluminum ice molds of theprior art. This is primarily the result of a lesser quantity of materialin the mold 30 and the housing 32 and greatly simplified configuration.

The heater 38 comprises part of the ice harvesting means 36. For reasonsmore fully pointed out hereinafter, the heater 38 is a low powerelectrical resistance element in heat exchanging relation with the mold30. After the thermostat 74 has sensed that the temperature in thedownstream ice piece cavity 52 has declined to a predetermined value,the thermostat 74 closes. If the stop-start switch 8 is closed, as willbe explained more fully hereinafter, the heater 38 is energized tocommence the ice harvesting operation.

The ice piece ejector 40 is illustrated as being of generallyconventional configuration and is quite similar to that disclosed in US.Pat. No. 3,163,018. The ejector 40 accordingly comprises a plurality ofpiston-like plates 86 formed integrally with the top of a thin elongatehorizontal bar 88 which passes between the ice forming cavities. Anejector rod 90 is secured to the vertical movement. The bushing 94includes one or more O-rings 96 for sealing against the rod 90. Thebushing 94 is threaded into a collar 98 which is held by a clamp 100. Incontrast with the amount of machining required in prior art ice molds,the only machining required in the mold 30 is the aperture in which thebushing 94 fits.

The driving means 42 comprises an electric motor 102 and a gear box 104of conventional design. The gear box 104 provides a rotatable output106. drivably connected to the linkage 44 for converting rotary motionof the output 106 into reciprocation of the ejector rod 90.

The linkage 44 comprises an enlarged hub 108 having thereon a crank orcam 110 spaced from the axis of the output 106. The cam 110 convenientlyc0mprises a screw 112 threaded into the hub 108 and a roller 114 mountedfor rotation thereon. The cam 110 is captivated in a generallyhorizontal slot 116 provided by a yoke 118 which is rigid with theejector rod 90. The yoke 118 is rigid with a framework 120 which isconstrained for vertical movement by a rod 122 passing through anopening 124 in the framework 120. It will accordingly be seen that thelinkage 44 is illustrated as comprising a Scotch yoke.

FIGS. 2-4 illustrate respectively the icemaking position of the icemaker10, the initiation of the ice harvesting cycle and the termination ofthe ice harvesting cycle. As the motor 102 is energized from theposition of FIG. 2, the output 106 rotates thereby providing the cam 110about the axis of the output 106. Revolution of the cam 110 causes theyoke 118 to move vertically as constrained by the rod 122.

The motor 102 and the heater 108 are energized substantiallysimultaneously. After an initial lost-motion movement of the linkage 44,the motor 102 stalls until the heater 38 melts a film of ice immediatelyadjacent the inner mold surface 50. As the heater 38 breaks the bondbetween the ice and the mold 30, the motor 102 begins movement therebyelevating the ejector 40. Consequently, the greatest force requiredduring the ice harvesting operation is at the initiation of ejectormovement. Accordingly, the linkage 44 is preferably designed to generatethe greatest force on the ejector rod 90 at the inception of upwardmovement thereof. An analysis of the linkage 44 reveals that a largeupward force produced thereby occurs when the cam lies in a sector 126adjacent the bottom of the path of movement of the cam 110. Accordingly,it is highly desirable that the linkage 44 commence ice harvestingmovement in the sector 126.

To this end, the motor 102 is de-energized by the circuit 48 on thedownstroke of the ejector rod 90 and a biasing spring 128 is providedfor biasing the rod 90 to its lower position and assuring fulldownstroke movement thereof as shown in FIG. 2.

The ice harvesting means 36 also includes a feeler arm 130 for sensingthe quantity of ice in the container 28. The feeler arm 130 isillustrated as passing through the housing 32 and journalled by suitablebushings 132 therein. As shown best in FIG. 5, the feeler arm 130 isrigidly connected to a lever 134 which is in turn pinned to a member136. The member 136 is constrained by a bracket 138 for verticalmovement and includes, at the lower end thereof, a pair of switchactuating members 140, 142. The switch actuating members 140, 142captivate a switch actuator 144 for the switch 84 illustrated in FIG. 6.

During ice harvesting the feeler arm 130 is raised out of the icecontainer 28 before ejection of the ice pieces and it thereafter dropsinto engagement with the ice pieces. To this end, there is provided anextension 146 underlying a bearing element 148 carried by the member136. As the linkage 44 is actuated, the framework and the extension 146thereon are elevated into contact with the bearing element 148. Assuggested in FIG. 4, during each ice ejection cycle the extension 146elevates the member 136 thereby raising the feeler arm substantially outof the container 28 and returns to the position as illustrated in FIG.2, allowing member 136 to assume a position determined by the engagementof feeler arm 130 with the ice pieces.

As the container 28 fills with ice, the feeler arm 130 assumes a more orless horizontal position upon engaging the ice pieces. Ultimately, asthe container 28 fills, the switch actuating member is held in anelevated position so that the switch actuator 144 opens the circuitleading to the motor 102 thereby preventing further harvesting of ice.As the container 28-is emptied, the feeler arm 130 again assumes a morenearly vertical position so that the switch actuating member 142 mayengage the switch actuator 144 and close the stop-start switch 84. Inthe alternative, the switch 84 may be of the normally closed type suchthat downward movement of the member 136 allows the switch actuator 144to return to the closed position.

An important part of the ice harvesting means 36 is the valve 46 forclosing or restricting the cold air passage 34. The valve 46 includes agate 150 mounted for movement in a suitable slot 152 between positionsopening and closing the passage 34. The gate 150 is manipulated betweenthese positions by an actuating arm 154. The actuating arm 154 ismovably mounted by a pivot connection 156 which is conveniently securedto the gear box 104. The free end of the actuating arm 154 is connectedto the gate 150 by a suitable lost motion connection. A cam follower 158is mounted on a projection 160 extending from the arm 154. The follower158 is captivated in a camming groove 162 on the back side of the hub108. As shown in FIG. 2, the follower 158 is positioned by the-cam track162 to depress the actuating arm 154 and thereby move the gate 150 outof the air passage 34. Since FIG.

2 illustrates the icemaking cycle of operation, air flow through thepassage 34 is unimpeded. At the commencement of the ice harvestingcycle, the hub 108 is rotated toward the position in FIG. 3. The camfollower 158 is moved laterally of the pivot connection 156 therebyraising the actuating arm 154 and moving the gate 150 to the closedposition. In the configuration of FIG. 3, it will be apparent that airflow through the passage 34 stops. By closing the valve 46, heattransfer from the inner mold surface 50 to the outer mold surface 54 isgreatly reduced.

The reduction of heat transfer from the inner mold surface 50 to theouter mold surface 54 has two important advantages. With the valve 46closed, the heater 38 needs only to warm the mold 30 sufficiently tobreak the ice adhesion bond. With the gate 46 open and cold air flowingthrough the passage 34, the heater 38 would necessarily be of greatercapacity since a substantial quantity of heat would be transferred tothe moving air stream rather than to the mold 30. Accordingly, a lowpower heater may be utilized. In prototypes of this invention, heatershaving 3040 watt capacity have proved satisfactory compared to 180 wattheaters used on presently commercially available icemakers. An importantpractical sidelight of this improvement in operating efficiency is thatthe heretofore conventional overheat safety thermostat, which isnormally in series with the thermostat 74, may be deleted since themaximum temperature rise of low power heaters is within the maximumallowable temperature rise for materials used in the icemaker 10.

There is another important advantage in ice harvesting efficiencyafforded by this invention. Referring to FIG. 3, it will be apparentthat the mold 30 is gaining heat immediately adjacent the heater 38 andgiving up heat away from the heater 38. By reducing heat transferefficiency during harvesting, the mold 30 does not need to be heated toas great a temperature to release the ice pieces in the cavities 52.Thus there is a reduction in total heat input required of the heater 38.

Because of the degradation of heat transfer efficiency duringharvesting, more sophiscated design improvements become practical. Forexample, breaking the adhesion of the ice pieces in the end cavitiescreates a greater stress on the ejector 40 and operating assemblytherefor because of the longer moment arm between the end cavities andthe axis of ejector movement. This may be obviated, if desired, bycontrolling heat input to break the adhesion bond in a particularsequence, for example end ice pieces first.

The switching mechanism 164 used in the control of the icemaker 10 issubstantially the same as illustrated in US. Pat. No. 3,163,018. Theswitching mechanism 164 comprises sequentially actuated switches 166,168. The switch 166 controls an energizing circuit for the motor 102while the switch 168 controls the solenoid 68 of the filling valve 66.The switches 166,168 are conveniently ganged together and manipulated byan actuator 170 having thereon a cam follow 172 which engages theperiphery 174 of the hub 108. The hub periphery 174 includes adepression 176 allowing selfbiased movement of the actuator 170 towardthe switch open position illustrated in FIG. 6.

At the termination of the icemaking cycle, the thermostat 74 closes. Ifthe feeler arm 130 senses a lack of ice in the container 28, the switch84 is closed. Thus, a circuit is completed to the heater 38 and themotor This rotation of the hub 108 initiates a plurality of functionsincluding closing of the valve 46 and closing of the switch 166.

The motor 102 stalls until the adhesion bond between the ice pieces andthe inner mold surface 50 is substantially weakened. The force imposedby the driving means 42 and linkage 44 is then sufficient to completebreakage of the'adhesion bond and allow upward movement of the rod 90and ejector 40 toward the position illustrated in FIG. 4. As the icecubes eject from the mold 30, they engage a suitable deflector 178 andfall into the container 24. Continued rotation of the hub 108 causesdownward movement of the ejector 40 and rod 90 from the position shownin FIG. 4 toward the position shown in FIG. 2. During the heatingperiod, thermostat 74 opens so that when the follower 172 passes intothe depression 176, opening switch 166, the motor 102 and heater 38 arede-energized. The hub 108 begins to coast to a stop. Engagement of thecam 110 with the bias spring128 causes the icemaker to come to rest inpreparation for an icemaking cycle.

As is apparent from FIGS. 1 and 6, a pair of leads 180, 182, whichenergize the circuit 48, are encased in suitable insulation to form acable 184 passing through the freezer side wall 16.

The icemaker affords a number of important advantages previouslymentioned. In addition, the icemaker 10 may be tested for operabilityprior to installation in a refrigerator.

I claim:

1. A self-harvesting icemaker, comprising: a mold providing ice pieceforming cavities, first means defining a cold air passage in heatexchanging relationship with the mold, second means for directing coldair -'through said cold air passage, third means operative duringharvesting for removing ice from the mold, said third means including aheater for warming the mold, and fourth means operative duringharvesting for restricting the cold air passage and precluding cold aircirculation through said cold air passage.

2. The self-harvesting icemaker of claim 1, wherein the first means isof a size sufficient relative to the mold for providing turbulent airflow at a preselected air flow rate.

3. The self-harvesting icemaker of claim 2, wherein the preselected airflow rate is in the range of between l-lO CFM.

4. The icemaker of claim 1 wherein the fourth means comprises a valveand means for moving the valve between positions opening and closing thepassage.

5. The icemaker of claim 4 further comprising means for substantiallysimultaneously energizing the heater and the means for moving the valve.

6. The icemaker of claim 4 wherein the third means includes an ejector,means for moving the ejector through the cavities, and means forenergizing the heater and for moving the valve to the passage closingposition prior to moving the ejector through the cavities.

1. A self-harvesting icemaker, comprising: a mold providing ice pieceforming cavities, first means defining a cold air passage in heatexchanging relationship with the mold, second means for directing coldair through said cold air passage, third means operative duringharvesting for removing ice from the mold, said third means including aheater for warming the mold, and fourth means operative duringharvesting for restricting the cold air passage and precluding cold airciRculation through said cold air passage.
 2. The self-harvestingicemaker of claim 1, wherein the first means is of a size sufficientrelative to the mold for providing turbulent air flow at a preselectedair flow rate.
 3. The self-harvesting icemaker of claim 2, wherein thepreselected air flow rate is in the range of between 1-10 CFM.
 4. Theicemaker of claim 1 wherein the fourth means comprises a valve and meansfor moving the valve between positions opening and closing the passage.5. The icemaker of claim 4 further comprising means for substantiallysimultaneously energizing the heater and the means for moving the valve.6. The icemaker of claim 4 wherein the third means includes an ejector,means for moving the ejector through the cavities, and means forenergizing the heater and for moving the valve to the passage closingposition prior to moving the ejector through the cavities.